Description of the Prior Art
Given the increasing desire of consumers neither to use or to consume products packed in recipients containing pollutant propellant gases, it is becoming increasingly necessary to design packaging which relies on atmospheric pressure for the dispensing and dosing of packed liquid and/or viscous products, as well as simple and safe handling of the packaging when the product is being used.
Even before the creation of pressurised containers, we already knew how to equip recipients intended to be used for dispensing doses of a particular product with heads fitted with a manual pumping and/or spray device. But, apart from such problems as the price of such a fitting, it demanded the inclusion of a plunger tube, extending from the pumping head to the base of the recipient.
French patent 2 353 455 already includes a design for a non-pressurised `drop by drop` dispenser for eye drops, which includes a head which has to be depressed, fixed to the neck of the bottle. When this particular dispenser is used, drops are formed by depressing the dispensing head; this depression is effected by the users' fingers, via radial elastic compression of two diametrically opposite ribs fitted to the neck of the dispenser. Independent of the fact that the size of the drop and thus the volume of the dose is defined by the dimensions of the different elements of the dispenser, which prevents the doses varying from one to dispenser to another, the head of the dispenser is activated directly, which implies that there is a risk of complete and repetitive depressing of the head which may result in poor premature malfunctioning of this head; such a device does not provide the required level of reliability if emptying the bottle necessitates a large number of strong actions to the head. Moreover, the use of such a `drop by drop` dispenser is essentially limited to liquids with low viscosity.
German utility model 9 000 921 already proposes a dosing dispenser which includes a bottle in the form of bellows housed in a sheath whose cover has a tube passing through it supported by the bottle, the lid of which is screwed into the sheath in order to compress the `bellows` and thus dispense the product contained in the bottle; such a dispenser can be difficult to handle, this difficulty increasing as the lid penetrates further down into the sheath.